Add Docker inventory plugin

plugins/inventory/docker.yml

+# This is the configuration file for the Ansible plugin for Docker inventory.
+#
+# Author: Paul Durivage <paul.durivage@gmail.com>
+#
+# Description:
+# This module queries local or remote Docker daemons and generates
+# inventory information.
+#
+# This plugin does not support targeting of specific hosts using the --host
+# flag. Instead, it it queries the Docker API for each container, running
+# or not, and returns this data all once.
+#
+# The plugin returns the following custom attributes on Docker containers:
+#    docker_args
+#    docker_config
+#    docker_created
+#    docker_driver
+#    docker_exec_driver
+#    docker_host_config
+#    docker_hostname_path
+#    docker_hosts_path
+#    docker_id
+#    docker_image
+#    docker_name
+#    docker_network_settings
+#    docker_path
+#    docker_resolv_conf_path
+#    docker_state
+#    docker_volumes
+#    docker_volumes_rw
+#
+# Requirements:
+# The docker-py module: https://github.com/dotcloud/docker-py
+#
+# Notes:
+# A config file can be used to configure this inventory module, and there
+# are several environment variables that can be set to modify the behavior
+# of the plugin at runtime:
+#    DOCKER_CONFIG_FILE
+#    DOCKER_HOST
+#    DOCKER_VERSION
+#    DOCKER_TIMEOUT
+#    DOCKER_PRIVATE_SSH_PORT
+#    DOCKER_DEFAULT_IP
+#
+# Environment Variables:
+# environment variable: DOCKER_CONFIG_FILE
+#     description:
+#         - A path to a Docker inventory hosts/defaults file in YAML format
+#         - A sample file has been provided, colocated with the inventory
+#           file called 'docker.yml'
+#     required: false
+#     default: Uses docker.docker.Client constructor defaults
+# environment variable: DOCKER_HOST
+#     description:
+#         - The socket on which to connect to a Docker daemon API
+#     required: false
+#     default: Uses docker.docker.Client constructor defaults
+# environment variable: DOCKER_VERSION
+#     description:
+#         - Version of the Docker API to use
+#     default: Uses docker.docker.Client constructor defaults
+#     required: false
+# environment variable: DOCKER_TIMEOUT
+#     description:
+#         - Timeout in seconds for connections to Docker daemon API
+#     default: Uses docker.docker.Client constructor defaults
+#     required: false
+# environment variable: DOCKER_PRIVATE_SSH_PORT
+#     description:
+#         - The private port (container port) on which SSH is listening
+#           for connections
+#     default: 22
+#     required: false
+# environment variable: DOCKER_DEFAULT_IP
+#     description:
+#         - This environment variable overrides the container SSH connection
+#           IP address (aka, 'ansible_ssh_host')
+#
+#           This option allows one to override the ansible_ssh_host whenever
+#           Docker has exercised its default behavior of binding private ports
+#           to all interfaces of the Docker host.  This behavior, when dealing
+#           with remote Docker hosts, does not allow Ansible to determine
+#           a proper host IP address on which to connect via SSH to containers.
+#           By default, this inventory module assumes all 0.0.0.0-exposed
+#           ports to be bound to localhost:<port>.  To override this
+#           behavior, for example, to bind a container's SSH port to the public
+#           interface of its host, one must manually set this IP.
+#
+#           It is preferable to begin to launch Docker containers with
+#           ports exposed on publicly accessible IP addresses, particularly
+#           if the containers are to be targeted by Ansible for remote
+#           configuration, not accessible via localhost SSH connections.
+#
+#           Docker containers can be explicitly exposed on IP addresses by
+#           a) starting the daemon with the --ip argument
+#           b) running containers with the -P/--publish ip::containerPort
+#              argument
+#     default: 127.0.0.1 if port exposed on 0.0.0.0 by Docker
+#     required: false
+#
+# Examples:
+#  Use the config file:
+#  DOCKER_CONFIG_FILE=./docker.yml docker.py --list
+#
+#  Connect to docker instance on localhost port 4243
+#  DOCKER_HOST=tcp://localhost:4243 docker.py --list
+#
+#  Any container's ssh port exposed on 0.0.0.0 will mapped to
+#  another IP address (where Ansible will attempt to connect via SSH)
+#  DOCKER_DEFAULT_IP=1.2.3.4 docker.py --list
+#
+#
+#
+# The Docker inventory plugin provides several enviroment variables that
+# may be overridden here.  This configuration file always takes precedence
+# over environment variables.
+#
+# Variable precedence is: hosts > defaults > environment
+
+---
+defaults:
+  host: unix:///var/run/docker.sock
+  version: 1.9
+  timeout: 60
+  private_ssh_port: 22
+  default_ip: 127.0.0.1
+hosts:
+#  - host: tcp://10.45.5.16:4243
+#    version: 1.9
+#    timeout: 60
+#    private_ssh_port: 2022
+#    default_ip: 172.16.3.45
+#  - host: tcp://localhost:4243
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